Xarb

This is a simple webpage that allows you to monitor the spread in Bitcoin prices between Coinbase (large US-based crypto exchange) and WazirX (India-based crypto exchange).

Getting started

Provision an API key from exchangerate-api.com. The free tier allows for 1000 requests/month. Then, export it:

export EXCHANGE_RATE_API_KEY=abc

Spin up Postgres backend and pgREST API:

docker-compose up -d

Initialize python virtual environment, install dependencies:

python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt

Run modules:

python fetch.py # Fetch WazirX data
python fetch_cb.py # Fetch Coinbase data
python fetch_fx.py # Fetch exchange rates from exchangerate-api.com

Optionally, set up cronjobs. For example:

# FX rates - fetch at 00:10 UTC
10 0 * * * /home/pi/wazirx/venv/bin/python3 /home/pi/wazirx/fetch_fx.py >> /home/pi/wazirx/fx.log 2>&1

## Wazirx - every 5 minutes
*/5 * * * * /home/pi/wazirx/venv/bin/python3 /home/pi/wazirx/fetch.py >> /home/pi/wazirx/fetch.log 2>&1

## Coinbase - every 5 minutes
*/5 * * * * /home/pi/wazirx/venv/bin/python3 /home/pi/wazirx/fetch_cb.py >> /home/pi/wazirx/fetch_cb.log 2>&1

You can spin up the frontend through the following.

source venv/bin/activate
gunicorn app:server

Deployment

I deployed this app using a Heroku app with a Heroku PostgresQL backend. A couple of GitHub Actions take care of populating the database with data, as well as deleting old rows (>2 weeks). UptimeRobot lets me know if the app goes down for some reason.

The whole setup cost $0.00.

Contributing

Create an issue or open up a branch and PR.